Prototype - click event by element class name

I am new to the prototype f开发者_C百科ramework and am trying something really simple and failing. I am trying to respond to a click event on a button like so:

$$('.btn').observe('click', respond);
function respond(event) {
    alert("hello");
}

Why isn't this working? Please help!

Unlike jQuery, handing selectors with multiple results in Prototype works a little differently. You need to handle each selected result separately using .each().

$$('.btn').each(function(element) {
    element.observe('click', respond);
})

This is one of the reasons I moved over to jQuery. The other reason: knowing jQuery is marketable and knowing Prototype is not.

Can be also be done with a single-liner, as someone already suggested in a comment:

$$('.btn').invoke('observe', 'click', respond);